The invention relates to chemotherapy and drug resistance.
Cancer chemotherapy commonly involves the administration of one or more cytotoxic or cytostatic drugs to a patient. The goal of chemotherapy is to eradicate a substantially clonal population (tumor) of transformed cells from the body of the individual, or to suppress or to attenuate growth of the tumor. Tumors may occur in solid or liquid form, the latter comprising a cell suspension in blood or other body fluid. A secondary goal of chemotherapy is stabilization (clinical management) of the afflicted individual's health status. Although the tumor may initially respond to chemotherapy, in many instances the initial chemotherapeutic treatment regimen becomes less effective or ceases to impede tumor growth. The selection pressure induced by chemotherapy promotes the development of phenotypic changes that allow tumor cells to resist the cytotoxic effects of a chemotherapeutic drug. Often, exposure to one drug induces resistance to that drug as well as other drugs to which the cells have not been exposed.